Apparatus for electrothermic reactions



y 1946. c. G. sulTs 2,399,951

APPARATUS FOR ELEGTROTHERMIC REACTIONS Filed March 16, 1943 2Sheets-Sheet 1 Pi l.

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Inventor: Chauncey G. Suits, by

H is Atb orne y.

May 7, 1946. c. G. SUITS APPARATUS FOR ELECTROTHERMIC REACTIONS FiledMarch 16, 1943 2 Sheets-She et' 2\\\\\&\\\\\\\\\\\\\\\\\\\\\\\\\&\\\\\\\\\\\\\\ Inventor: ChaunCey G.Sui'bs, b fi Q JJMZ y l-li Patented May 7, 1946 APPARATUS FORELECTROTHERMIC REACTIONS Chauncey G. Suits, Schenectady, N. Y., assignorto General Electric Company, a corporation of New York Application March16, 1943, Serial No. 479,348

9 Claims.

The present application is a continuation-inpart of my prior applicationSerial No. 380,640, filed February 26, 1941, which in turn is acontinuation-in-part of an earlier application Serial No. 275,203, filedMay 23, 1939.

The present invention relates to the production of transient electricarcs which are suitable for the generation of gases, and in particularhydrocarbon gases such for example as acetylene, the claims hereof beingdirected to apparatus features of the invention.

I have discovered that when an electric current of properLv chosenvoltage and amperage is conducted through a bed or column of contactingparticles or pellets of conducting material, such as carbon for example,immersed in a carbo-hydrogen compound of poor conductivity, such forexample as mineral oil, the formation of transient electric arcs takesplace between the particles because of the relatively high transitionresistance between contacting particles. The electric arcs are ofmomentary duration, and are accompanied by the evolution of gas. Theindividual arcs appear to be' terminated by the evolution of gas, whichdisturbs the position of arcing particles with respect to neighboringparticles. Under conditions to be set forth, the evolved gas consistspreponderantly of hydrogen and acetylene.

Referring to the drawings, the apparatus illustrated by Fig. 1 includes,in addition to the essential features of an apparatus for carrying outmy invention, also various automatic auxiliary devices and variousnon-essential structural details; Fig. 2 illustrates a modificationcontaining a rotating electrode; and Fig. 3 is a diagram of athree-phase arrangement.

The gas-generating apparatus comprises an are chamber I which isprovided with cooperating electrodes 2 and 3 which are spaced apart.Between the electrodes is a bed or stratum of discrete particles ofconductive material 4, the particles being arranged movably incontacting relation. During operation transient arcs are formed at pointof contact between adjacent particles which bridge the gap between theelectrodes. The material 4 preferably consists of loose lumps orparticles of carbonaceous material such for example as coke, coal,amorphous carbon' or graphite. The carbonaceous particles may have adiameter ranging from about 1 5 inch up to one inch, the preferred sizebeing about one-quarter inch. Although comminuted carbonaceous materialis preferred as the material 4, the employment of carbides, metals, orother conductive material is not excluded.

As the relatively non-conducting liquid I may employ a liquidhydrocarbon such as mineral oil or benzol. An oil of vegetable orbiologic origin, as for example turpentine, oleic acid, or mixtures suchas a solution of sugar in water also may be used. For the presentpurposes such various organic materials will be termed generically ascarbo-hydrogen compounds. The liquid fills the spaces between theparticles in the bed of comminuted material between the electrodes. Theliquid conveniently is introduced through ducts 5 extending through thelower electrode 2 as indicated. The distance between the electrodes 2, 3is not critical. This spacing ordinarily should be about one inch, andmay be up to many inches in length.

Although the structure of the conversion chamber and electrodes may bevaried, depending on the reaction to be carried out, the nature of thereacting ingredients and other factors, it may be said for illustrativepurposes that the container I may consist of suitable metal such as ironand may be provided with a lining which in the apparatus illustratedconsists of two layers, a layer 6 of non-conducting material such asheat-hardened phenolic resin or the like, and layer 1 of Alundum whichis adjacent to the arcing zone. The electrodes 2, 3 may consist ofgraphite. The electrode 3 is attached to a stem 9 consisting of copperor other suitable conductive material which is surrounded by a sheath l0of Alundum, or other suitable refractory insulating material. Theelectrode stem 9 is insulated from the container by a bushing ll ofsuitable insulating material as, for example, a phenolic resincomposition.

The non-conducting liquid is introduced by a conduit I 2 whichcommunicates with the ducts 5 and leaves the reaction chamber through astrainer I3. The liquid material is conveyed through a conduit I by amotor-driven pump I5 into a settling tank It from whence it is returnedby the conduit I! to the reaction chamber. In the tank I 6, fineparticles such as carbon black, which may be formed in the liquid, arelargely removed by the strainer II. The upward flow of the liquidsupplied by the conduit l2 and the ducts 5 to the arc chamber in thedescribed circulatory course agitates the conducting particles 4 andthus maintains them in movably contacting relation in the liquid betweenthe electrodes. Additional amounts of oil may be introduced through aconduit ll containing a one-way valve I! as will be later described.Assuming the space between the electrodes to contain carbon granules andthe space between the granules to be filled with a suitable liquid, suchas mineral oil, in which the particles move freely due to-theirbuoyancy, a current of at least about an ampere at suitable potential ofat least 30 volts is supplied to the electrodes by the conductors 20.20'. Preferably the voltage should be materially higher. For example,alternating current at 60 cycles and at a potential in the range fromseveral hundred to one thousand volts may be employed for an electrodeseparation of one inch.

Vigorous arcing occurs between the points of contact of the granules,each arc being accompanied by the generation of gas, the arc in turnbeing extinguished by the gas evolution. While a ballast or seriessteading resistance in the arc cir-. cult is not essential in all cases,an impedance 2| is shown and is desirable. The duration of the transientarcs ranges from about .00006 second to .01 second, the arcs ofrelatively long duration in this range being more common.

Under the conditions above described, that is,

when particles or lumps of carbonaceous material such as coke aboutone-quarter inch in size are introduced in loose contact betweengraphite electrodes spaced apart aboutone inch, and

when a body of mineral oil or the like envelops 'not, appreciabl exceedthat of the liquid. The

reaction chamber, which, as illustrated, is large relative to the massof liquid acted upon, also functions as a heat-dissipating means. Thesolid conducting particles donot reach oil-cracking temperatures exceptperhaps at minute local areas which are highly heated only temporarilyby arcs terminating thereon. Although the oil becomes heated in. thezones of the transient arcs between the carbon particles, it does notbecome heated as Y a whole sufliciently to be cracked" or destructivelydecomposed thermally, that is, other than by the action of the arcs. Forexample, the body of mineral oil may assume, outside of the arcing zonesduring the operation of the process, a temthe contacts in the circuit25. 2i 0! the motor 21. The motor is connected by the gears 24 to a feedscrew 29 located in a supply chamber 30. Due to the operation 01' thefeed screw 29, additional granules of carbonaceous material are chargedfrom time to time into the reaction chamber I to make u for losses. 7

It the level of the liquid in the reaction chamber is reduced below apredetermined level, it may be replenished by manual control orautomatically. A closed float chamber 32 is connected to the reactionchamber by conduits ll, 34. If the liquid falls below a predeterminedlevel, then, by the operation of automatic mechanism, additional liquidis introduced. The float 35 which is linked to a switch it closes theenergizing circuit 31, 38 of a motor 39 which is mechanically connectedto a pump 40 supplying oil to the oil inlet II. The switch ihhas beenconventionally indicated to represent any suitable form of switch, suchfor example as'a mercury switch of the form described in United StatesLetters Patent No. 2,101,092. A one way valve I! is provided to holdpressure in the tank I when required. The energizing circuit 31, 38 hasnot been shown in its entirety and the source of current has beenomitted to avoid complicating the drawing.

The gaseous pressure in the reaction chamber also may be automaticallycontrolled by a relay 4| which is connected to a Sylphon bellows 42. Forexample, if the pressure oi! the gas should rise, above a predeterminedlimit, then the contacts of the relay 4| are opened, thereby effectingthe operation of a circuit breaker 43 which open-circuits the powersupply lines 20, 20. Ordinarily alternating current is supplied to thecircuit 20, 20'. Direct current, however, may be perature within therange of about 250 to 300 .tween the electrodes 2 and 3. In an automaticapparatus, the reduction of the current in the conductor 20' weakens itsefiect on the solenoid of the relay 23 until its armature 24 bridgesemployed to operate the main arc. Preferably a cooling coil 44 isprovided in the upper part of the arc chamber in order to condenseungasified vapors although the upper part of the reaction chamber evenin the absence of such cooling coil, will function as a cooling andcondensing means.

The condensate runs back into the reaction space i where it contactswith the arcs and is decom posed to form acetylene and other gases.

In the apparatus shown in Pig. 2, one of the electrodes is rotatedtransversely'with respect to its cooperating electrode and thereby isrend'ered capable of agitating the particles of coke or other conductingmaterial. This apparatus, like the apparatus of Fig. 1, comprises acontainer 45 provided with a suitable lining 40. At the base of thischamber is a stationary carbonaceous electrode 41, for example, anelectrode 01' graphite, to which is connected an electric terminal 48 bya bolt 49. The arc chamber is closed by a cover 50 consisting ofsuitable insulating material such as an asbestos composition which isbonded with Portland cement. The cover is arranged to be fastened downupon the container wall by the threaded bolts 51 which engage with nuts52. Passing through the cover is an insulating sleeve 53 which mayconsist of the same asbestos composition. It is pressed upon a shoulderof the cover aperture by a ring 54, a suitable packing being provided asindicated. The external threads oi the ring 54 engage with the internalthreads of a ring 55 which is bolted to the cover 50. Within the sleeve53 is helda metal'sleevc 56 within which turns a shaft 51, the lower endof which carries a conical bearing member 58. The latter is urged intoseating relation to another bearing member 59 by a spring 65 at theupper end of the shaft 51. This spring is held under compression betweena shoulder 6| on the shaft and an insert 62 in the top of the sleeve 56.The lower end of the rotatable shaft 51 carries an ofl'set electrode 63which is held eccentrically by a pin 84 on a link plate 85. Theelectrode 83 is urged upwardly against the plate 65 by a spring 88 whichis held under compression in a recess as shown between a shoulder 61 anda pressure plate 68 bearing on the electrode 64.

The electrode shaft 51 is arranged to be rotated by a gear 18 engagingwith a driving member H. Electric energy is supplied by a stationarybrush contact 12 hearing against a rotating ring contact 13. Theeccentrically mounted electrode 63 when rotated exerts a stirring efiecton a mass 15 of carbon granules which are immersed in a charge 16 ofhydrocarbon oil, or the like, in the arc chamber. The gaseous productsproduced by arcing escape from the reaction chamber through a flue 11.The rotatable electrode and attached parts are arranged to be lifted byengagement with a ring 18.

Initially stirring of the charge is not required as with oil of ordinaryviscosity the coke particles remain localized in the bottom of theconversion chamber between the electrodes and normal arcing as abovedescribed occurs therein. As arcing proceeds and oil decompositionproceeds with the formation of gaseous products, the residue becomesthickened, largely due to accumulation of carbon black."

When about one-half of the oil volume has been converted to gas, theviscosity of the remaining volume of oil becomes sufliciently increasedto cause the coke to become dispersed throughout the body of thickenedoil, thereby decreasing the mobility of the conducting particles so thatsatisfactory arcing no longer occurs. If it is attempted to increase therate of arcing by introducing additional charge of coke particles, thecondition of thickening is found aggravated and free movement of thecoke particles is prevented.

When under this condition the electrode is caused to be slowly rotatedby the driven gear member 10, the number of conducting paths in thethick paste of viscous oil and carbon granules is increased, beingdirectly proportional to the rate of movement of the electrode 63.Hence, the arcing rate can be controlled by the rotation rate. Even whenthe viscosity of the pasty mixture is so high that no arcing whateverwould take place with a stationary electrode, a satisfactory rate ofarcing and oil conversion may be maintained with an electrode speed ofone revolution in three seconds.

In Fig. 3 there is shown conventionally a threephase apparatus forproducing gas in accordance with my invention. The bottom electrode 80is connected by a conductor 8| to the neutral point of a star-woundthree-phase transformer. The opposite terminals of the three coils areconnected respectively by the conductors 83, 84 and 85 to the electrodes86, 81 and 88. The tank 45 contains a body 16 of mineral oil or othersuitable carbo-hydrogen liquid and conductive pellets as described inconnection with Figs. 1 and 2.

When employing mineral oil or other hydrocarbonaceous liquid as thequenching agent in the arc chamber, the gases evolved consist of amixture of hydrogen, acetylene, and small amounts of other hydrocarbons.The percentage of acetylene varies from about 30 to 40 per cent byvolume, depending on the operating conditions.- In general, theeiiiciency of the apparatus increases with the size of the arc chamberwith increase of impressed voltage and with increase in temperature ofthe mineral. oil or other quenching liquid.

The efficiency of acetylene production is about .009 kilowatt hour perliter (.255 kilowatt hour per cubic foot), although even higherefiiciencies have been obtained under carefully controlled conditions.

It is desirable,in order to obtain maximum efliciency of gas production,to so operate the apparatus that the ordinary conducting current betweenthe electrodes should be kept at a minimum, the arc current then beingat a maximum. The are current is evidenced on the oscillograph by asuccession of high, narrow peaks in the current. 'When usingordinary-alternating current, the absence of arcing component would beevidenced by the current through the apparatus having the usual smoothsine wave form. When arcing occurs, sharp peaks are superimposed on thesine wave which progressively becomes reduced relatively until atmaximum arcing the sine wave becomes replaced by narrow, high peaks ofcurrent.

Apparently the evolution of gas at the points of arc formation forcesthe arcin c m between the loose particles apart until the arcs areextinguished and the gases are suddenly cooled. The reaction 2C+H2=C2Hz,which normally would tend to be established in a liquid hydrocarbon inhigh temperature equilibrium, thus is forced to the right, resulting inthe evolution of acetylene. While I do not wish to be limited by anytheory of operation, I believe that the production of acetylene isconditioned by numerous transient arcs formed between the looseparticles of conducting material creating numerous localized reactionzones which are heated to high temperatures for intervals of extremelyshort duration, and being subsequently cooled at a high rate uponcessation of arcing in each local reaction zone.

The gas mixture may be separated and purified by known chemical methodsforming no part of the present invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A gas generator comprising the combination of a reaction and coolingchamber, a fixed electrode at the base of said chamber, a secondelectrode fixedly spaced from said first-mentioned electrode, arrangedto be rotatable and having an offset portion moving in a circular pathduring the rotation of said second electrode, means for rotating saidsecond electrode, a bed of carbon particles between said electrodes,means for supplying a liquid to be gasified to said bed, means forconducting an arc-supporting current between said electrodes and meansfor carrying away gaseous reaction products from said chamber.

2. A gas generator comprising the combination of a reaction chamber, astratum of electrically conducting, loosely contacting pellets therein.fixedly spaced cooperating electrodes electrically contacting with saidstratum of pellets, means for enveloping said pellets in a liquid to begasified, means for conducting current to said electrodes, mechanicalmeans for stirring said stratum of pellets, and means for carrying awaygaseous products from said chamber.

3. A gas generator comprising the combination of a reaction chamber,electrodes therein, one of which is rotatable and ofiset with respect toan axis passing through said electrodes, means for conveying electricenergy to said electrodes, a bed of conducting particles located betweensaid electrodes, said particles being relatively movable with respect toone another, means for enveloping said particles in a liquid to begasifled, means for rotating said offset electrode to rearrange saidconducting" particles with respect to one another, thereby facilitatingthe formation oi electric arcs therebetween, and means for carryinggaseous products from said chamber.

4. ,A gas generator comprising the combination of an elongated reactionchamber, one portion of which functions as a cooling means,heat-resisting electrodes in another portion oi said chamber, saidelectrodes being fixedly spaced from one an other, a bed of relativelymovable and electrically contacting conducting pellets between saidelectrodes, means for stirring said pellets, said chamber providing alsomeans for holding a body of liquid in enveloping relation to said bed,means for conveying electric energy to said electrodes, and means forcarrying away gas from said reaction chamber. 5. An apparatus forgenerating gas from a liquid carbo-hydrogen compound of poorconductivity which consists of a reaction chamber, ilxedly spacedcooperating electrodes the ends of which are separated by a gap, freelymovable, non-consolidated conducting particles located between the endsof said electrodes at said gap, means for maintaining a body of saidliquid in enveloping. relation to said particles, means for agitatingsaid particles to maintain them in loose suspension in said liquid,means whereby electric energy may be conveyed to said electrodes forforming transient electric arcs between said particles, and means forcollecting the gas resulting from the decomposition of said liquid.

6. An apparatus for generating gas from mineral oil comprising thecombination of a reaction chamber, fixedly spaced electrodes in saidchamber, discrete carbonaceous pellets located between said electrodes,means for, maintaining a body of mineral oil in enveloping relation tosaid pellets, means for agitating said pellets to maintain said pelletsin loosely contacting suspension in said oil, means for formingtransient electric arcs between said pellets, the heat-dissipatingcapacity of said apparatus being adequate to maintain such oil belowdecomposition temperature outside of the influence of said arcs, andmeans for collecting the gas formed by the action of said arcs on saidoil.

7. A gas generator comprising the combination of electrodes which areiixedly spaced apart, means for enveloping the spaced ends of saidelectrodes with a body of liquid to be decomposed. a bed of carbonpellets in said liquid adjacent said spaced ends, and tree to move inand out of aresupporting relation between said spaced electrodes, meansfor agitating said pellets, means for forming transient electric arcsbetween said particles whereby said liquid is decomposed, means forcondensing ungasiiled vapors in said generator, and means for carryingaway gas resulting from the decomposition oi. said liquid.

8. A gas generator comprising the combination of an elongated normallyvertical reaction chamber, fixedly spaced, arc-supporting electrodestherein which are separated by a gap near the bottom of said chamber,means for enveloping the spaced electrodes with a body of liquid, a bedof carbon pellets immersed in said liquid, said pellets being free tomove in and out of circuitcompleting relation to said electrodes, one ofsaid electrodes being rotatable and being constructed with an eccentricportion engaging with said bed for agitating said particle whilemaintaining the gap between said electrodes substantially unchanged,means for rotating said rotatable electrode, and means for carrying awaygaseous products from said chamber- 9. A gas generator comprising thecombination of a reaction chamber, a bed 01' carbon particles betweensaid electrodes, means for supplying to said bed a liquid to begasified, said particles having suillcient buoyancy to be freelymovable, spaced cooperating electrodes one of which is ro tatable and isprovided with an eccentric portion so oriented with respect to thecooperating electrode that during the rotation of said eccentric portionsaid carbon particles are agitated while the spacing oi said electrodesis maintained substantially unchanged, means for rotating said rotatableelectrode, means for conveying electric energy to said electrodes, andmeans for carrying away gaseous reaction products from said electrodes.

CHAUNCEY G. SUITS.

